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Reduced rates of metolachlor and atrazine for weed control in corn /Mangan, Francis Xavier 01 January 1991 (has links) (PDF)
No description available.
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Pre-emergence herbicide programs for weed control in soybean (Glycine max) and the effect of rainfall amount on herbicide activityMeyer, Caleb Knox 08 August 2023 (has links) (PDF)
Preemergence (PRE) herbicides are used to control weeds and reduce pressure on postemergence (POST) herbicides. However, knowledge of length of control each herbicide provides, as well as the amount of activation rainfall required for adequate weed control, is unknown in Mississippi soybean production. Twenty-one PRE applied soybean herbicides were evaluated for their duration of residual control for five weeks over twelve site years on three weed species from 2021-2022. Some differences in control following herbicide application used on certain weed species were observed at different times. However, most PRE herbicides resulted in adequate (greater than or equal to 90%) control of weed species evaluated up to 35 days after emergence. Also, four PRE herbicides were evaluated in the greenhouse to quantify the amount of rainfall needed for activation when applied to three different soil textures. These data suggest that rainfall recommendations vary by herbicide and soil texture, and some herbicides were effective at controlling weed species at low rainfall amounts (less than 12.7mm).
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Mitigation of herbicide resistance development among weed species in cotton and peanutCalhoun, Justin S 10 December 2021 (has links)
Herbicide resistance development among weed populations in cotton and peanut is becoming increasingly difficult to manage. If resistant populations continue to persist, weed control practices for producers will become less efficient and more costly. The objective of this research was to evaluate alternative weed control techniques designed to mitigate herbicide resistance development for their agronomic and economic impact on weed management systems. Studies were conducted in 2019, 2020, and 2021 at multiple locations in Mississippi and Arkansas investigating multiple techniques including the addition of soil surfactants in herbicide tank mixtures, increasing SOAs utilized in peanut herbicide programs, applying non-labeled herbicides to cotton with post-directed spray placement, and applying complete residual herbicide programs in cotton. Our results suggests that some novel strategies incorporated into existing weed management programs, can provide sufficient control of troublesome weed species and conserve crop yield and profit returns. For example, the use of post-directed application placement allowed for non-labeled herbicides to be applied to cotton without detrimental effects, thus increasing potential options for POST weed control within that crop. Additionally, weed control, seed cotton yield, and net returns were not affected when only residual herbicides were applied in season-long weed control programs as opposed to the standard of mixed, foliar and residual programs. This indicates that high selection pressure associated with foliar chemistries which leads to resistance development, can be alleviated through the adoption of alternative strategies.
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Harvest Weed Seed Control: An Integrated Weed Management Strategy for Organic and Conventional Production SystemsHaring, Steven C. 07 September 2017 (has links)
Harvest weed seed controls (HWSC) destroy weed seeds that are retained by the plant at crop harvest, which would typically be spread by the harvester along with other field residues. HWSC exploits coincidental maturity between crops and weeds, so an experiment was designed to collect weed seeds as they shatter throughout the growing season and through a simulated harvest delay. This experiment monitored four economically important broadleaf species and two grass species in a soybean (Glycine max (L.) Merr.) field. Results indicated that broadleaf species shattered seed at rates accelerating through the growing season, while grass species shattered more seed early in the growing season. Field experiments in organic and conventional winter wheat (Triticum aestivum L.) fields infested with Italian ryegrass (Lolium perenne L. ssp. multiflorum (Lam.) Husnot) compared two HWSC techniques to grower-standard weed management programs in each system, including both no-till and full-till standard treatments in the conventional system. Italian ryegrass populations were monitored, and wheat yield was measured both before and after HWSC application. In both organic and conventional cropping systems, HWSC treatments did not provide better Italian ryegrass control than the grower-standard treatments. The conventional program including tillage boosted Italian ryegrass populations. These results suggest that HWSC treatments did not enhance Italian ryegrass control compared to grower-standard practices in either the organic or conventional systems. Additionally, broadleaf weeds may retain enough seeds to be viable targets for HWSC. Incorporating best practices, such as a timely crop harvest, is key for understanding and optimizing HWSC. / Master of Science
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Studies on the effect of contact herbicides as top-killers of alfalfaSwartley, Harold William. January 1952 (has links)
Call number: LD2668 .T4 1952 S93 / Master of Science
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Interaction of weed emergence, weed density, and herbicide rate in soybeanNdou, Aifheli Meshack January 1900 (has links)
Doctor of Philosophy / Department of Agronomy / Johanna A. Dille / Challenges in weed management include occurrence of multiple weed species in the
field, variable emergence among weed species, different spatial distribution and weed densities,
which leads to the persistence of weed patches. The overall objective of this research was to
understand the interaction of weed emergence, weed density, herbicide choice, and herbicide rate
in soybean. Specific objectives were 1) to characterize the seedbank and emergence patterns of
shattercane (Sorghum bicolor L.), prickly sida (Sida spinosa L.), and ivyleaf morningglory
(Ipomoea hederacea Jacq.) including initial, peak, end, and duration of emergence in response to
crop and herbicide treatments in soybean, and 2) to evaluate large crabgrass (Digitaria
sanguinalis L.), shattercane, Palmer amaranth (Amaranthus palmeri S.), and velvetleaf (Abutilon
theophrasti Medik.) mortality and dry weight reduction in response to herbicide rates across
varying weed densities as well as to determine the influence of velvetleaf growth stage and
density on herbicide efficacy. In the emergence study of 2006 to 2008, four treatments were nocrop,
no-residual herbicide, half-rate of residual herbicide and full-rate of residual herbicide.
Reduction in weed emergence was observed over the years in the same species patch. Species
emerged in mid-May in both years, coinciding with soybean planting. Extended emergence was
observed for shattercane when moisture was low and temperature high, while for prickly sida
and ivyleaf morningglory, extended emergence was observed when moisture was high and
temperature low. Applying residual herbicide decreased weed emergence. Herbicide choice was
the whole plot, herbicide rates were subplots and weed densities were sub-subplots in field
experiments conducted in 2006 and 2007. Shattercane was more susceptible to both glyphosate
and clethodim than large crabgrass. Increasing large crabgrass density reduced percent mortality
with clethodim, while with glyphosate, density did not affect both species mortality. Shattercane
dry weight was reduced to 0 g per plot with 0.1X labeled rate of clethodim or glyphosate while
0.5X of the labeled rate reduced dry weight of large crabgrass to 0 g per plot. For broadleaf
weeds, higher percent mortality was observed with glyphosate than with lactofen at high
densities. Palmer amaranth was more susceptible than velvetleaf. Velvetleaf response was
density dependent, such that increasing density did not increase dry weight. Velvetleaf growth
stage was of importance, as stage affected herbicide efficacy, with higher mortality achieved at
the two-leaf stage than the four- and six-leaf stages. For glyphosate, 0.125X of labeled rate on
velvetleaf density of 5 seedlings per pot achieved more than 90% mortality when applied at the
two-leaf stage, but dropped to 60 and 50% mortality when applied at the four- and six-leaf stage,
respectively. The trend was the same for velvetleaf at a density of 30 seedlings per pot, which
had 80, 60, and 55% mortality for the two-, four-, and six-leaf stages, respectively. Weed
managers and farmers have the opportunity to better select herbicide choice and rate based on
weed species, weed emergence patterns, and weed density.
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Influence of formulation and application variables in relation to the performance of glyphosate and imazapyr for control of Imperata cylindrica (L.) RaeuschelTownson, Jane K. January 1990 (has links)
No description available.
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Weed Control for Wheat and Barley in the Low Deserts of ArizonaOttman, Michael, Tickes, Barry 04 1900 (has links)
3 pp. / Revised / Weeds can be a problem in wheat and barley especially where crop rotation is not practiced. An integrated approach to weed management can be followed. Chemical treatments are important tools in weed management to maintain yield and quality and prevent proliferation of weeds that could affect future crops.
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Chemical Control of Annual WeedsArle, H. Fred, Hamilton, K. C. 04 1900 (has links)
No description available.
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A comparative study of the biology of Cirsium arvense (L.) Scop. and Equisetum arvense L. in relation to their cultural controlKolo, Musa G. Matthew January 1995 (has links)
No description available.
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